Last week I was driving my daughters to a birthday party when I pulled over at an intersection to let a fire engine through. Naturally, one driver, in a green Nissan, decided to use the speeding truck as his personal blocking back, tailing close behind and passing those of us who had pulled to the side. He made just enough progress before getting to the stoplight that I found myself totally cut off once the truck passed, forced to sit there and wait through yet another cycle of the light. I could have just let the transgression go, of course, but I felt an uncontrollable urge to honk my horn at Green Nissan as we waited at the red light.

In fact, I didn’t just give a quick honk of irritation. No, I gave him two distinct honks—the first a brief one to announce my presence with authority, the second a longer, drawn-out one to remind Green Nissan, as he waited at the light, that 1) he did something wrong, 2) I know he did something wrong, and 3) I know that he knows he did something wrong.

* * *

. . . [D]istracted, it took me a few minutes to realize that, two miles later, I was still right behind Green Nissan. And I had made a few turns since the fire truck went by. I started to get the sinking sensation that we might be headed to the same destination, a hypothesis further supported by the sight of a car seat in the back of his car as well.

Why this gave me an uneasy feeling, I cannot pinpoint precisely, as there were multiple factors at play. But of one thing I’m quite sure—the freedom I felt to honk my horn aggressively at Green Nissan from my safe, anonymous seat behind the windshield quickly dissipated at the mere thought of having a face-to-face encounter with him in an open parking lot.

Was I afraid of an actual physical confrontation? Not really. . . .

More likely, I was thinking about the fact that I really don’t enjoy confrontations of any type, my zealous horn-honking notwithstanding. Moreover, I don’t relish being thought of as a jerk, and it was beginning to dawn on me that this was probably precisely what Green Nissan thought of me. Maybe I hadn’t been a jerk per se, but had I overreacted at least a tad? Sure. And while all these thoughts were running through in my head, I found myself following Green Nissan through yet another pair of turns, one left, one right. I slumped a bit further down in my seat as I drove on.

* * *

The experience just served to crystallize for me how powerful it is to feel anonymous in a situation, particularly when it comes to the manifestation of aggression. As [Situationist contributor] Phil Zimbardo has written, feeling anonymous and deindividuated leads college students to administer greater levels of shocks to fellow student in laboratory studies. Along similar, albeit graver lines, perpetrators of violence, whether vigilante or state-sponsored in origin, often disguise themselves in hoods, masks, or make-up. And it’s no coincidence that the harshest, most aggressive verbal swipes taken in cyberspace usually come from anonymous sources as well.

Research even speaks directly to my very experiences on the road last week, illustrating that feelings of anonymity lead to increases in aggressive driving. In retrospect, that’s exactly how I felt behind the wheel when Green Nissan cut me off: anonymous. I knew he could catch a glimpse of me if he turned to look, but I assumed we were heading in different directions and I was never going to see him again. That liberated me to act in ways I’d never dream of in face-to-face interaction.

* * *

. . . . Just yet another demonstration of the power of subtle situational factors: It’s amazing how something as simple as sitting behind the wheel of a car can be enough to lead to such transformations in identity and behavior.